COMSOL example model results do not match with Mathematical Model


by Oscar6330
Tags: cantilever, comsol
Oscar6330
Oscar6330 is offline
#1
Jun12-11, 12:43 AM
P: 29
Hi! I started to look into freq response analysis of a cantilever beam using COMSOL. Luckily COMSOL already has an example model "Model Library>> Structural mechanics module>>Dynamics and Vibrations>>rotating blade". While not changing anything in the model and with Omega=0 and Cloris =0, I get the following results

Resonance Freq1 = 84.36
Resonance Freq2 =528.84
Resonance Freq3 =949.31

Resonance Freq4 =1316.00
Resonance Freq5 =1481.41
Resonance Freq6 =2882.00

But Euler beam theory (options>>constants) gives me the following

Resonance Freq1 = 84.36
Resonance Freq2 =528.66
Resonance Freq3 =1862.89

Resonance Freq4 =3650.55
Resonance Freq5 =6034.61
Resonance Freq6 =9064.89

Clearly the results do not match after 2nd natural/ resonance freq. I am quite sure that COMSOL example model cannot be wrong but there is something odd. Some elaboration would be appreciated
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Mech_Engineer
Mech_Engineer is offline
#2
Jun13-11, 11:56 AM
Sci Advisor
PF Gold
Mech_Engineer's Avatar
P: 2,234
You're wanting to solve a cantilever beam modal analysis, but used a rotating blade vibration analysis. How are the boundary conditions defined?


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